6,924 research outputs found

    Last planner and critical chain in construction management: comparative analysis

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    This paper endeavours to compare the Last Planner System of production control and the Critical Chain production management method. This comparison is carried out in the context of construction management. The original prescription and the evolution of the practice are examined regarding both approaches, and the similarities and differences are noted. Based on these considerations, gaps in the two approaches are identified and the potential of a synthesis of them is explored

    Abnormal enhancement of electric field inside a thin permittivity-near-zero object in free space

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    It is found that the electric field can be enhanced strongly inside a permittivity-near-zero object in free space, when the transverse cross section of the object is small and the length along the propagation direction of the incident wave is large enough as compared with the wavelength. The physical mechanism is explained in details. The incident electromagnetic energy can only flow almost normally through the outer surface into or out of the permittivity-near-zero object, which leads to large energy stream density and then strong electric field inside the object. Meanwhile, the magnetic field inside the permittivity-near-zero object may be smaller than that of the incident wave, which is also helpful for enhancing the electric field. Two permittivity-near-zero objects of simple shapes, namely, a thin cylindrical shell and a long thin rectangular bar, are chosen for numerical illustration. The enhancement of the electric field becomes stronger when the permittivity-near-zero object becomes thinner. The physical mechanism of the field enhancement is completely different from the plasmonic resonance enhancement at a metal surface

    Squeezing electromagnetic energy with a dielectric split ring inside a permeability-near-zero metamaterial

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    A novel electromagnetic energy squeezing mechanism is proposed based on the special properties of permeability-near-zero metamaterials. Nearly no energy stream can enter a conventional dielectric region positioned inside a permeability-near-zero material. When a source is surrounded by a dielectric split ring (encloser with a gap opened), the electromagnetic energy generated by the source is forced to propagate through the gap. When the gap is narrow, the energy stream density becomes very large and makes the magnetic field enhanced drastically in the gap. The narrow gap can be long and bended. This provides us a method to obtain strong magnetic field without using resonance enhancement.Comment: 17pages, 4 figure

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    Non-Linear Deformations of Liquid-Liquid Interfaces Induced by Electromagnetic Radiation Pressure

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    The idea of working with a near-critical phase-separated liquid mixture whereby the surface tension becomes weak, has recently made the field of laser manipulation of liquid interfaces a much more convenient tool in practice. The deformation of interfaces may become as large as several tenths of micrometers, even with the use of conventional laser power. This circumstance necessitates the use of nonlinear geometrical theory for the description of surface deformations. The present paper works out such a theory, for the surface deformation under conditions of axial symmetry and stationarity. Good agreement is found with the experimental results of Casner and Delville [A. Casner and J. P. Delville, Phys. Rev. Lett. {\bf 87}, 054503 (2001); Opt. Lett. {\bf 26}, 1418 (2001); Phys. Rev. Lett. {\bf 90}, 144503 (2003)], in the case of moderate power or a broad laser beam. In the case of large power and a narrow beam, corresponding to surface deformations of about 50 micrometers or higher, the theory is found to over-predict the deformation. Possible explanations of this discrepancy are discussed.Comment: RevTeX4, 19 pages, 4 figures. Sec. IIIB rewritten, 4 new references. To appear in Phys. Rev.

    Associations between selected demographic, biological, school environmental and physical education based correlates, and adolescent physical activity

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    The study investigated associations between selected physical activity correlates among 299 adolescents (90 boys, age 12-14 years) from 3 English schools. Physical activity was assessed by self-report and accelerometry. Correlates represented biological, predisposing, and demographic factors as described in the Youth Physical Activity Promotion Model. Boys engaged in more self-reported (p < .01) and accelerometer assessed physical activity than girls (p = .02). Positive associations between sex (male), BMI, Perceived PE Ability, Perceived PE Worth, number of enrolled students, and physical activity outcomes were evident (p < .05). Schoolbased physical activity promotion should emphasize sex-specific enhancement of students' perceived PE competence and enjoyment

    WHOLE-BODY PROTEIN METABOLISM IN MATURE AND GROWING HORSES RECEIVING PREDOMINANTLY FORAGE DIETS

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    There has been limited investigation as to whether a predominantly forage-based diet can provide adequate amounts of limiting amino acids (AA) to horses. The first objective was to determine if AA supplementation of AA believed to be limiting to protein synthesis in forage-based diets would affect measures of whole-body protein metabolism in sedentary mature horses. The effect of forage type (timothy or alfalfa) and AA supplementation (lysine, threonine or histidine) on plasma urea nitrogen (PUN) and AA concentrations and measures of whole-body phenylalanine kinetics were evaluated. There was no effect of either forage type or AA supplement on rates of whole-body protein synthesis (P \u3e 0.05). The second objective was to determine the effects of either timothy or alfalfa hay supplemented with either a high or low protein ration balancer on measures of whole-body protein metabolism in yearling horses. The effect of forage type and the ration balancer protein level on concentrations of PUN, plasma AA and measures of wholebody phenylalanine kinetics were evaluated. There was no effect of treatment on average daily gain (P = 0.18). When horses consumed the alfalfa-based diets, rates of phenylalanine flux, oxidation and use for protein synthesis were greater than when they consumed timothy-based diets (P \u3c 0.05). Phenylalanine use for protein synthesis was not affected by the protein level of the ration balancer (P = 0.3). Yearling horses achieve greater rates of protein synthesis when fed alfalfa-based diets, compared to timothy-based diets, supplemented with a low protein ration balancer

    Does Waldorf education offer a well-rounded and integrated experience that prepares students for higher grades and life in general?

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    This thesis research focuses on the study of Waldorf education and how it benefits the whole child. It begins by looking at Rudolf Steiner’s Waldorf educational program and its foundational history and then takes an in depth look at the key elements of its rich philosophy and pedagogy. The literature review focuses on the key question, ‘Does this 100 year-old teaching philosophy encourage a more well-rounded and integrated educational experience than traditional public schools?’ The review highlights four broad topics in relationship to Waldorf education. These include: Educating the Whole Child; Education for the Three Stages of Childhood; Early Childhood Education; and Integrated Education. The review also compares Waldorf education to traditional schools. A mixed methods research project was conducted to go more in depth into the topic of the value of Waldorf education. The overall concentration of the mixed methods research was to answer two central questions. The first question was, ‘How do parents feel about their children\u27s Waldorf education?’ The second question was, ‘What aspects of their children’s Waldorf school experiences are important?’ The study was carried out by conducting interviews and surveys with Waldorf parents. The interviews focused on the aspects of children’s Waldorf education that influences their present and future schooling and beyond. The survey focused on two questions, ‘Does Waldorf curriculum offer a well-rounded education?’ and ‘Does Waldorf curriculum prepare students for the upper grades and life more generally?’ The study revealed that parents highlighted many key elements they feel are integral to educating the whole child - hands, heart, and head. The interview research showed that parents place a high value on many themes some of which include: Child Development and Developmentally Appropriate Practices; Special Techniques for Teaching Math; Nature Connections and Science Lessons; The Arts Curriculum; and Social-Emotional Development. The survey research disclosed some important themes described by the statistical data and Pearson Correlations. Some of these themes are: How Academics are Taught using a Waldorf Curriculum; Holistic Education and Educating the Whole Child – Hands, Heart, and Head in Relationship to Waldorf Education; and the Importance of Math Being Taught through the Waldorf Curriculum. The results were clear – parents do appreciate their children’s Waldorf education. They feel that it is a fundamental curricular program that helps their children to benefit from its important strategies, achieve their optimal development, and become prepared for upper grades and life in general
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